Swivel-head grapple

ABSTRACT

This disclosure pertains to a two-line grapple in which one line closes the grapple and a second line opens the grapple. The linkage employed comprises four bars and four pivot points and in this respect is similar to that of a clamshell bucket as opposed to a tong grapple. The closing line operatively shortens the distance between the jaw pivot and the uppermost pivot by exerting a compressive force in each of two actuating links which are themselves joined at one end by an uppermost pivot and are attached at their other ends to points on the jaws intermediate the jaw pivot and the lower ends of the jaws. An opening line or lifting means supports the jaws through tensile forces in the actuating links and gravity causes the jaws to open. Means have been adapted whereby a swivel-head provides adjustable guidance for the closing line as well as an opening impulse to the jaws when the weight of the grapple is shifted from a closing line to an opening line or lifting means attached to the swivel-head.

United States Patent [72] Inventor NormanAllenJohnson 5325 10th Ave.. Delta 742 British Columbia, Canada [21] ApplNo. 844,271 [22] Filed July 24,1969 [45] Patented June 1,1971

[54] SWIVEL-HEAD GRAPPLE 4 Claims, 6 Drawing Figs.

[52] U.S.C1 294/112, 37/183,37/187 [51] lnt.Cl B66cl/00 [50] Fieldol'Search 294/110- [56] References Cited UNITED STATES PATENTS 916,965 4/1909 Atherton 37/184 1,180,394 4/1916 Hayward.=.... 37/184 1,779,702 10/1930 Harrington 294/112 1,988,135 1/1935 Odman 294/112 3,082,031 3/1963 Lindberg 294/111 3,186,752 6/1965 Kaplan 294/106 FOREIGN PATENTS 805.067 5/1951 Germanym. 294/112 6,400,671 7/1965 Netherlands. 294/112 Primary Examiner-Harvey C. Hornsby ABSTRACT: This disclosure pertains to a two-line grapple in which one line closes the grapple and a second line opens the grapple. The linkage employed comprises four bars and four pivot points and in this respect is similar to that ofa clamshell bucket as opposed to a tong grapple. The closing line operatively shortens the distance between the jaw pivot and the uppermost pivot by exerting a compressive force in each of two actuating links which are themselves joined at one end by an uppermost pivot and are attached at their other ends to points on the jaws intermediate the jaw pivot and the lower ends of the jaws. An opening line or lifting means supports the jaws through tensile forces in the actuating links and gravity causes the jaws to open. Means have been adapted whereby a swivelhead provides adjustable guidance for the closing line as well as an opening impulse to the jaws when the weight of the grapple is shifted from a closing line to an opening line or lifting means attached to the swivel-head.

PATENTEUJUN nan I 358212? SHEEIIUFZ PATENTEDJUN H971 SHEET 2 [1F 2 SWIVEL-HEAD GRAPPLE This invention relates to novel improvements in devices which are known in the art to which they pertain as grapples, or to devices such as clamshell buckets and tongs that belong to or are of the general character of grapples. In their simplest form grapples and tongs are substantially symmetrical fourbar mechanisms whose operation is effected by supporting lines which counter the effects of gravity on the mass of the grapple.

More particularly, in the field of logging grapples are used for yarding and loading logs. Principle requirements for logging grapples are compactness, lightness, simplicity of construction, adequacy of closing force, dependability of opening mechanism, and effective loading of closing and opening cables into the grapple mechanism.

It is the principle object of this invention to provide an improved grapple assembly, especially designed for log handling, of compact and light construction, and whose overall height when fully open is substantially the same as its overall height when fully closed.

It is a further object of this invention to provide ajaw-closing force substantially equal to or greater than the lifting force carried by a closing line.

Yet another object of this invention is to provide a positive and dependable opening mechanism based on an impulse imparted to the grapple jaws ultimately by an opening line or lifting means.

Still another object of the invention is to provide a swivelhead which adjusts to substantial variations in closing line angle in the plane of the grapple linkage, adjustment perpendicular to said plane being automatic through pivoting ofa log in the grapple jaws.

It is still another object of the invention to provide actuating links in which their common pin connection ensures that stresses in said links will be substantially tensile for opening and compressive for closing, bending stresses therein being substantiallynonexistant.

Still further objects and advantages of the present invention reside in the details of construction of the grapple assembly.

These and further objects of the invention will be evident from a study of the following disclosure and the accompanying drawings which illustrate improved details of construction of a preferred embodiment of the invention. This embodiment is merely exemplary and is not intended to detract from the full scope of the invention as set out in the annexed claims.

In the drawings, wherein like numerals refer to like parts:

FIG. '1 is a front view showing a grapple assembly in accordance with the present invention and with jaws of the grapple shown in their open position;

FIG. 2 is a side view of the arrangement of FIG. 1;

FIG. 3 is a vertical transverse section substantially in the plane indicated by section line 3-3;

FIG. 4 is a front view showing a grapple assembly as in FIG. 1 but wherein the jaws are in their fully closed position;

FIG. 5 is a sectional view taken substantially along section line 5-5;

FIG. 6 is a sectional view taken substantially along section line 6-6.

Referring now to the drawings, the grapple assembly forming the subject matter of this invention is particularly adapted for two line operation. In the open position as in FIG. 1, an opening line 10 carries the weight of the grapple assembly, gravity holding the jaws open and closing line 11 remaining slack. Closing line 11 passes through leader 51 of swivel'head 12, about an arcuate portion of sheave 13 (particularly when the weight of the grapple is carried by closing line 11), thence along path 14, about jaw pivot pin 15 by means of sheave 16, thence along path 17, about link pivot pin 24 by means of sheave l8, and finally along path 19 to pivot pin 20. As is shown in FIG. 5, closing cable 11 passes through pivot pin 20 and is secured thereto by ferrule 21, the ferrule also holding pin 20 between jaw wing plates 22 and 23. It will be appreciated that when the weight of the grapple is transferred to closing line 11 from opening line 10, the jaw pivot pin 15 will move toward link pivot pin 24, an accumulated length of closing line from paths 14, 17 and 19 passing through leader 51 and causingjaws 25 and 26 to close.

Clearly, asjaws 25 and 26 close, the lower ends 29 and 30 of the grapple jaws will approach one another and eventually overlap to the extent allowed either by an object therebetween or by interfacing stops 27 and 28. It is also evident that as closing of the grapple jaws occurs, the swivel-head assembly 12 will rotate about pivot pin 24, leader 51 thereby always maintaining alignment of closing line 11 with the groove of sheave 13 but substantially avoiding significant sidewise pressures on the closing line 11 other than that applied by sheave 13.

It will be appreciated that the force in closing line 11 will be equal to the weight of the grapple plus the weight of a grappled object. In the embodiment of the invention shown the compressive force or closing force applied to sheave 18 by closing line 11 passing along paths 17 and 19 will be substantially borne by link pivot pin 24 and thence by actuating links 31 and 32. It is evident from'the location of link pivot pin 24 and actuated pivot pins 33 and 34 that the closing compressive forces in actuating links 31 and 32 will be substantially greater than the closing force in closing line 11. In like manner it can be shown that the opening tensile force in each of the actuating links 31 and 32, when the grapple assembly is carried by opening line 10, is substantially greater than one half the weight of the grapple assembly.

Turning now to the mode of construction of the present invention, and referring still to the drawings, it may be seen first that the jaws 25 and 26 are fabricated from steel plate. Jaw 25, in which sheave 16 is housed, is fabricated from plates 35, 23, and 22. To provide additional bearing and lateral spatial clearance between the jaws, boss 36 is affixed to plate 22. Plate 23 is scabbed on the side of plate 35. Plate 22 is set in to allow only enough lateral clearance for the width of sheave 16. At the time, plate 37 is affixed to plates 35, 23, and 22 and spacer 38 provides rigidity while allowing the maintenance of opening 39, which opening prevents build up of foreign matter in the enclosure of sheave l6. Jaw 26, essentially one plate, has boss 40 affixed thereto to provide additional bearing strength at pivot pin 15. Bosses 41 and 42 affixed respectively to jaws 25 and 26 are provided to make up the space required between the side bars of actuating links 31 and 32, as dictated by the lateral spatial requirements of swivel guide 12 and sheaves l3 and 18. Plates 22 and 23 are extended past jaw pivot pin 15 to provide a connecting pivot 20 for closing line 11. Jaw 26 is also extended past jaw pivot pin 15 to provide a counterweight 59 which contributes to the initiation of opening of jaws 25 and 26. Interfacing stops 49 and 50 affixed to jaws 25 and 26 respectively limit the opening of the jaws.

Actuating links 31 and 32 are comprised of flat plates 43 and 44 and 45 and 46 respectively. These flat plates are separated by a continuous web member 47 and 48 respectively. The curved and formed ends of web plates 47 and 48 provide rigidity for actuating links 31 and 32 while still allowing space within the structure of the grapple assembly for counterweight 59 on jaw 26 and lever extension 60 on jaw 25. Web members 47 and 48 must be suitably notched to accommodate closing line 11 along paths 14, 17 and 19.

Swivel-head 12 comprises leader 51 for closing line 11, a

cable protective cover 52 of arcuate length such that substantial angular movement of swivel-head 12 is possible without core 52 fouling closing line 11 along paths 17 and 19, a backplate 53 and hub 54. Clearly hub 54 shares pin 24 with actuating links 31 and 32. In addition, sheaves l3 and 18 ride on the outside of hub 54, thus ensuring uniform distribution into pin 24 of the forces carried by sheaves l3 and 18. Pivot means 55 is provided in back plate 53 and thereto is attached opening line 10.

The outer periphery of backplate 53 is broken up by a radially inset portion 62 limited by dogs 56 and 57. Dogs 56 and 57 interact with lug 58 which itselfis affixed to sideplate 46 of actuating link 32. Dogs 56 and 57 thus limit the angular motion of swivel-head 12 with respect to actuating link 32. In addition, it will be appreciated that when the support of grapple and load is transferred from closing line ll to opening line 10, swivel-head 12 will turn abruptly, an impulse thereby being imparted by dog 56 to lug 58 and being transmitted to the jaws 25 and 26 by way of actuated pivot 34. While the present invention is designed to open under the influence of gravity, it is clear that the above mentioned impulse will contribute significantly to the initiation of opening particularly when the grapple closes fully after having missed a log. To further increase cycling speed through the powered initiation of opening when the grapple is fully closed, a further dog 61 associated with swivel-head 12 is used. When the grapple weight is transferred from closing line 11 to opening line 10, dog 6] imparts a smart downward impulse to the rounded surface of counterweight member 59 ofjaw 26 thus positively initiating an opening actron.

It will be appreciated that the foregoing discloses only a preferred embodiment of the invention. Further, many modifications, changes and equivalents will readily occur to those skilled in the present art, particularly in view of the above teachings. Therefore, the present invention is not to be construed as limited to the specific details illustrated and described above.

The embodiments of the invention in which claim exclusive property or privilege are defined as follows:

1. A grapple assembly comprising a pair of jaws, jaw pivot means pivotally interconnecting the upper ends of said jaws for scissorslike reiative motion, a pair of actuating links, link pivot means pivotally interconnecting one end of each of said actuating links, actuated pivot means pivotally interconnecting the other ends of said actuating links each to one of said jaws, said actuated pivot means being disposed on said jaws at points intermediate said jaw pivot means and the lower ends of said jaws, swivel guide means pivotally interconnected to said link pivot means, lifting means connected to said swivel guide means, swivel guide motion-limiting dog means secured to said swivel guide and lug means secured to one of said actuating iinks, said dog means and said lug means being disposed face to face relation in the limited positions of said swivel guide means, flexible closing means having one end interconnected to at least one of said jaws and passing through said swivel guide means whereby tensioning of said flexible closing means shortens the distance between said link pivot means and saidjaw pivot means.

2. A grapple assembly as defined in claim 1, including an actuating extension secured to said swivel guide means in contacting relation with an actuated extension secured to one of said jaws when said jaws are in overlapping relation whereby lifting said grapple assembly by said lifting means causes said actuating extension to impart a jaw opening impulse to said actuated extension.

3. A grapple assembly as defined in claim 1 including grapple opening means comprising dog means secured to said swivel guide and lug means secured to one of said actuating links, said dog means and said lug means being disposed on the same side of a plane containing the axes of said jaw pivot means and said link pivot means on which said lifting means is connected to said swivel guide means, said dog means and said lug means themselves being disposed in face to face relation when said grapple assembly is supported by said lifting means.

4. A grapple assembly comprising a pair of jaws, jaw pivot means pivotally interconnecting the upper ends of said jaws for scissorsiike relative motion, a pair of actuating links, link pivot means pivotally interconnecting one end of each of said actuating links, actuated pivot means pivotally interconnecting the other ends of said actuating links each to one of said jaws, said actuated pivot means being disposed on said jaws at points intermediate said jaw pivot means and the lower ends of said jaws, swivel guide means pivotaiiy interconnected to said link pivot means, swivel guide motion-limiting dog means secured to said swivel guide and lug means secured to one of said actuating links said dog means and said lug means bein disposed in face to face relation 1 the limited positions of sat swivel guide means, lifting means operatively interconnected to the upper end of one of said actuating links, a flexible closing means having one end operatively secured to a lever arm extension at the upper end of one of said jaws and entrained about a first sheave means rotatably mounted on said link pivot means and entrained about a second sheave means rotatably mounted on said link pivot means and passing through said swivel guide means, whereby tensioning of said flexible closing means will shorten the distance between said link pivot means and saidjaw pivot means. 

1. A grapple assembly comprising a pair of jaws, jaw pivot means pivotally interconnecting the upper ends of said jaws for scissorslike relative motion, a pair of actuating links, link pivot means pivotally interconnecting one end of each of said actuating links, actuated pivot means pivotally interconnecting the other ends of said actuating links each to one of said jaws, said actuated pivot means being disposed on said jaws at points intermediate said jaw pivot means and the lower ends of said jaws, swivel guide means pivotally interconnected to said link pivot means, lifting means connected to said swivel guide means, swivel guide motion-limiting dog means secured to said swivel guide and lug means secured to one of said actuating links, said dog means and said lug means being disposed in face to face relation in the limited positions of said swivel guide means, flexible closing means having one end interconnected to at least one of said jaws and passing through said swivel guide means whereby tensioning of said flexible closing means shortens the distance between said link pivot means and said jaw pivot means.
 2. A grapple assembly as defined in claim 1, including an actuating extension secured to said swivel guide means in contacting relation with an actuated extension secured to one of said jaws when said jaws are in overlapping relation whereby lifting said grapple assembly by said lifting means causes said actuating extension to impart a jaw opening impulse to said actuated extension.
 3. A grapple assembly as defined in claim 1 including grapple opening means comprising dog means secured to said swivel guide and lug means secured to one of said actuating links, said dog means and said lug means being disposed on the same side of a plane containing the axes of said jaw pivot means and said link pivot means on which said lifting means is connected to said swivel guide means, said dog means and said lug means themselves being disposed in face to face relation when said grapple assembly is supported by said lifting means.
 4. A grapple assembly comprising a pair of jaws, jaw pivot means pivotally interconnecting the upper ends of said jaws for scissorslike relative motion, a pair of actuating links, link pivot means pivotally interconnecting one end of each of said actuating links, actuated pivot means pivotally interconnecting the other ends of said actuating links each to one of said jaws, said actuated pivot means being disposed on said jaws at points intermediate said jaw pivot means and the lower ends of said jaws, swivel guide means pivotally interconnected to said link pivot means, swivel guide motion-limiting dog means secured to said swivel guide and lug means secured to one of said actuating links, said dog means and said lug means being disposed in face to face relation in the limited positions of said swivel guide means, lifting means operatively interconnected to the upper end of one of said actuating links, a flexible closing means having one end operatively secured to a lever arm extension at the upper end of one of said jaws and entrained about a first sheave means rotatably mounted on said link pivot means and entrained about a second sheave means rotatably mounted on said link pivot means and passing through said swivel guide means, whereby tensioning of said flexible closing means will shorten the distance between said link pivot means and said jaw pivot means. 